This list of fossil fish research presented in 2021 is a list of new taxa of jawless vertebrates, placoderms, acanthodians, fossil cartilaginous fishes, bony fishes, and other fishes that were described during the year, as well as other significant discoveries and events related to paleoichthyology that occurred in 2021.
Jawless vertebrates NameNoveltyStatusAuthorsAgeType localityLocationNotesImagesFalxcornusGen. et sp. novIn pressMeng & GaiDevonian (Lochkovian)Xishancun FormationA member of Galeaspida belonging to the family Tridensaspidae. Genus includes new species F. liui.HongshanaspisGen. et sp. novValidLiu et al.Silurian (Telychian)Qingshui FormationA member of Galeaspida belonging to the family Hanyangaspidae. Genus includes new species H. inexpectatus.JiangxialepisGen. et sp. novValidLiu et al.Silurian (Telychian)Fentou FormationA member of Galeaspida belonging to the group Eugaleaspidiformes. The type species is J. retrospina.QushiaspisGen. et sp. novValidJiang et al.Early DevonianXujiachong FormationA member of Galeaspida. Genus includes new species Q. elaia.
Jawless fishes research A study on the phylogenetic relationships of cyathaspidids is published by Elliott, Lassiter & Blieck (2021). Miyashita et al. (2021) report larval and juvenile forms of four stem lampreys from the Paleozoic era (Hardistiella, Mayomyzon, Pipiscius and Priscomyzon), including a hatchling-to-adult growth series of Priscomyzon, and report that the studied larvae display features that are otherwise unique to adult modern lampreys, and lack the defining traits of ammocoetes. A study on the anatomy and likely feeding ecology of Mesomyzon mengae, based on data from new, well-preserved specimens, is published by Wu, Chang & Janvier (2021). A study on the histology of the dermal skeleton in Procephalaspis oeselensis, Aestiaspis viitaensis, Dartmuthia gemmifera and four species of Tremataspis is published by Bremer et al. (2021), who interpret their findings as indicative of the emergence of the complex pore-canal system in Tremataspis through the modification of the structures already present in other taxa. A study aiming to determine whether the earliest vertebrates may have swum under various conditions without a clearly-differentiated tail fin, based on data from an abstracted model of Metaspriggina walcotti, is published by Rival, Yang & Caron (2021). A study on the morphological and functional diversity of osteostracan and galeaspid headshields, and on its implications for the knowledge of the ecology of the immediate jawless relatives of jawed vertebrates, is published by Ferrón et al. (2021). Redescription of Nochelaspis maeandrine is published by Meng, Zhu & Gai (2021). A study on the anatomy of a dorsal head shield of Kalanaspis delectabilis is published by Tinn et al. (2021).
Placoderms Name Novelty Status Authors Age Type locality Country Notes ImagesBianchengichthysGen. et sp. novValidLi, Zhu & Zhu in Li et al.Silurian (Ludfordian)Xiaoxi FormationA placoderm closely related to the last common ancestor of bony and cartilaginous fishes. The type species is B. micros.LeptodontichthysGen. et sp. novJobbins et al.Devonian (Givetian)Taboumakhlouf FormationA member of Arthrodira belonging to the family Plourdosteidae. The type species is L. ziregensis.
Placoderm research Zhu et al. (2021) use CT scanning to reveal the endocast of Brindabellaspis stensioi, and evaluate the implications of its anatomy for the knowledge of the phylogenetic relationships of early jawed vertebrates. Redescription of the anatomy of the headshield of Parayunnanolepis xitunensis is published by Wang & Zhu (2021). Description of new fossil material of Palaeacanthaspis vasta from the Devonian (Lochkovian) Chortkiv Formation (Ukraine), and a study on the phylogenetic relationships of this species, is published by Dupret et al. (2021).
Acanthodians Name Novelty Status Authors Age Type locality Country Notes ImagesDobunnacanthusGen. et comb. novValidDearden et al.DevonianA new genus for "Vernicomacanthus" waynensis Miles (1973)Nostolepis digitusSp. novValidLi et al.Devonian (Lochkovian)Xitun FormationNostolepis qujingensisSp. novValidLi et al.Devonian (Lochkovian)Xitun Formation
Acanthodian research A study on the development of teeth in acanthodians, and on its implications for the knowledge of the evolution of teeth of jawed vertebrates, is published by Rücklin et al. (2021). A study on the anatomy of teeth, jaws and associated oral structures of acanthodians, and on their implications for the knowledge of the evolution of dentition of modern cartilaginous fishes, is published by Dearden & Giles (2021).
Cartilaginous fishes NameNoveltyStatusAuthorsAgeType localityLocationNotesImagesAquilolamnaGen. et sp. novVullo et al.Late Cretaceous (Turonian)Agua Nueva FormationA probable planktivorous shark placed in the new family Aquilolamnidae, of uncertain placement. Possibly a member of Lamniformes. The type species is A. milarcae.Carcharhinus dudoniSp. novValidCanevet & LebrunMioceneA species of Carcharhinus.Carcharhinus pedroniiSp. novValidCanevet & LebrunMioceneA species of Carcharhinus.Carcharhinus tingaeSp. novValidCicimurri & EbersoleEocene (Bartonian)()A species of Carcharhinus.Cladodus gailensisSp. novValidFeichtinger et al.Carboniferous (Serpukhovian)DracopristisGen. et sp. novValidHodnett et al.Late Carboniferous (Kasimovian)Atrasado Formation()A medium-sized ctenacanthiform shark known from a complete skeleton with soft tissue. The type species is D. hoffmanorum.DurnonovariaodusGen. et sp. novValidStumpf et al.Late Jurassic (Tithonian)Kimmeridge ClayA member of the family Hybodontidae. The type species is D. maiseyi.FavusodusGen. et sp. novValidLi et al.Triassic (Ladinian–Carnian)A member of Euselachii. Genus includes new species F. orientalis.JunggarensisGen. et sp. novValidRoelofs et al.Devonian (Famennian)Genus includes new species J. ambiguus.KeichouodusGen. et sp. novValidLi et al.Triassic (Ladinian–Carnian)A member of Euselachii. Genus includes new species K. nimaiguensis.KeuperodusGen. et comb. novValidIvanov, Duffin & RichterLate Triassic (Carnian)Arden Sandstone Formation Grabfeld FormationA member of the family Jalodontidae. Genus includes "Phoebodus" brodiei Woodward (1893) (interpreted by Ivanov, Duffin & Richter, 2021 as a senior synonym of "Phoebodus" keuperinus Seilacher, 1948).LilamnaGen. et comb. novValidGreenfieldlate Eocene or Cretaceous (uncertain) A possible member of the family Pseudoscapanorhynchidae. The type species is "Archaeolamna" apophysata Li (1997).MaiseyacanthusGen. et sp. novValidBronsonCarboniferous (Mississippian)Fayetteville Shale()A symmoriiform. The type species is M. ozarkanum.MaiseyodusGen. et comb. novValidLong et al.Devonian (Emsian)Cravens Peak BedsA member of the family Mcmurdodontidae; a new genus for "Mcmurdodus" whitei Turner & Young (1987).MoskovirhynchusGen. et sp. novValidPopov & ShapovalovLate JurassicA chimaera belonging to the family Callorhinchidae. Genus includes new species M. robustus.NebriimimusGen. et sp. novValidCollareta et al.Pliocene (Zanclean)A member of Rajiformes, possibly a skate. The type species is N. wardi.Negaprion cossardiSp. novValidCanevet & LebrunMioceneA species of Negaprion.Phoebodus curvatusSp. novValidIvanovDevonian (Givetian–Frasnian)ProtochimaeraGen. et sp. novValidLebedev & Popov in Lebedev et al.Carboniferous (Viséan–Serpukhovian)Dashkovo Formation()A chimaera. Genus includes new species P. mirabilis.Pseudocorax kindlimanniSp. novIn pressJambura, Stumpf & KriwetLate Cretaceous (Cenomanian)Sannine FormationPtychodus maghrebianusSp. novIn pressAmadori et al.Late Cretaceous (Turonian)ReifellaGen. et sp. novValidIvanov in Ivanov et al.Permian (Roadian)Cutoff Formation()A member of the family Anachronistidae. Genus includes new species R. lata.RosaodusGen. et sp. novValidLi et al.Triassic (Ladinian–Carnian)A member of Elasmobranchii of uncertain phylogenetic placement. Genus includes new species R. xingyiensis.Strophodus indicusSp. novValidSharma & SinghMiddle Jurassic (Bathonian)Jaisalmer FormationMarine hybodont sharkStrophodus jaisalmerensisSp. novIn pressKumar et al.JurassicJaisalmer FormationA hybodont shark.Taeniurops sergiomoraiSp. novLaurito & ValerioMiocene–Pliocene (Messinian–Piacenzian)Uscari FormationA stingray, a species of Taeniurops.Triodus aeduorumSp. novValidLuccisano et al.Early PermianAutun BasinVallisodusNom. novValidDuffinLate TriassicPenarth GroupA member of Neoselachii; a replacement name for Vallisia Duffin (1982).
Cartilaginous fish research Description of new fossil material of Gualepis elegans from the Lower Devonian of Yunnan (China), and a study on the phylogenetic relationships of this fish, is published by Cui et al. (2021). Mottequin et al. (2021) reject the interpretation of Spiraxis interstrialis as chondrichthyan egg cases, and evaluate the implications of this reinterpretation for the knowledge of the evolution of oviparity in cartilaginous fishes. Description of the first known skull remains of Onchopristis numidus from the Cretaceous Kem Kem Group (Morocco), and a study on the anatomy and phylogenetic relationships of this species, is published by Villalobos-Segura et al. (2021), who name a new family Onchopristidae. New, exceptionally well-preserved skeleton of Asteracanthus ornatissimus, preserved with teeth that markedly differ from other teeth referred to Asteracanthus, is described from the Tithonian Altmühltal Formation (Germany) by Stumpf et al. (2021), who interpret this specimen as indicating that Asteracanthus and Strophodus represent two valid genera distinct from all other hybodontiforms. A study on the morphological diversity of teeth of lamniform sharks from mid-Cretaceous assemblages in Australia, and on its implications for the knowledge of the composition of mid-Cretaceous shark communities and their recovery in the aftermath of the Cenomanian-Turonian boundary event, is published by Bazzi, Kear & Siversson (2021). A study on the biomechanics of teeth of five species of Otodus, aiming to assess the functional significance of morphological trends in otodontid teeth and to test whether the morphology of otodontid teeth enabled the transition from piscivory to predation on marine mammals and the evolution of titanic body sizes, is published by Ballell & Ferrón (2021) A study on a bonebed in the Oligocene Chandler Bridge Formation (South Carolina, United States) with a large sample of Carcharocles angustidens dominated by small teeth is published by Miller, Gibson & Boessenecker (2021), who interpret this bonebed as a nursery area for C. angustidens. A study on growth patterns, reproductive biology and likely lifespan of Otodus megalodon is published by Shimada et al. (2021). Perez, Leder & Badaut (2021) present a novel method for estimating body size in fossil lamniform sharks, and attempt to determine the body size of Otodus megalodon. Revision of the fossil record of the extant tiger shark and the extinct members of the tiger shark lineage is published by Türtscher et al. (2021). Redescription of Striatolamia tchelkarnurensis is published by Malyshkina (2021). Shark teeth which might represent the first occurrence of the blacknose shark in the Pacific Ocean are described from the Pliocene Upper Onzole Formation (Ecuador) by Collareta et al. (2021), who evaluate the implications of this finding for the knowledge of the evolutionary history of the blacknose shark and the whitenose shark. Two fossil teeth of the blacktip shark are reported from lower Pliocene marine deposits of Tuscany (Italy) by Collareta et al. (2021), representing the first known occurrence of this species in the fossil record from both Europe and the Mediterranean Basin.